Chipper bit and holder

ABSTRACT

Bits clamped between fixed blocks and removable blocks are arranged in a spiral row around a hollow rotating chipping drum. Each bit is curved, a particular form of bit being substantially cylindrically curved. Each bit is clamped between bit-holding blocks enegaging opposite bit faces with the bit-cutting edges projecting beyond the periphery of the chipping drum. The cutting edges are concave with adjacent cutting edges meeting in a cusp.

Vanek July 1, 1975 CHIPPER BIT AND HOLDER [56] References Cited [75]Inventor: Stanley Donald Vanek, Seattle, U I ATES P TENTS Wash.3,2l9,076 l 1/1965 Logan Et al l44/24l X 3,327,746 6/1967 A d et a].[731 Ass'gneei gg g s ggg 3,675,693 7/1972 v2.13? 144 241 [221 Filed:Apr. 6, 1973 Primary ExaminerDonald R. Schran [211 pp No 348 858Attorney, Agent. or Firm-Robert W. Beach Related U.S, Application Data[57] ABSTRACT Continuation-impart Of ay Bits clamped between fixedblocks and removable 1973; 5; 335748391 whlch 3 blocks are arranged in aspiral row around a hollow igzg g z g zg g rotating chipping drum. Eachbit is curved, a particular form of bit being substantiallycylindrically curved.

Each bit is clamped between bit-holding blocks ene- [52] 144/230 144/2412302 5 gaging opposite bit faces with the bit-cutting edges projectingbeyond the periphery of the chipping drum. 2; jz h The cutting edges areconcave with adjacent cutting l 0 edges meeting in a cusp.

14 Claims, 19 Drawing Figures PATENT JUL 1 SHEEI .lll QQIIITI 1CI-IIPPER BIT AND HOLDER This application is a continuation-in-part ofmy application Ser. No. l4l.595 filed May l0. 1971, U.S. Pat. No.3,757,839 which is a continuation-in-part of the application ofThomas W.Nicholson, Ray B. .Iorgensen and Stanley Donald Vanek, Ser. No. 883,038.filed Dec. 8, I969, for Peripheral Chipper for Round Log Sections whichresulted in U.S. Pat. No. 3,66l.l92.

This application relates particularly to cutting bits for hollowrotating chipping drums and structure for holding such bits relative tosuch a drum including clamping blocks engaging opposite sides of eachbit.

A principal object of the present invention is to provide chipper bitswhich can be held securely in the periphery of a chipping drum, yetwhich can be removed for sharpening and replaced quickly.

A further object is to provide cooperating blocks to engage oppositefaces of a bent cutting bit which can be clamped together readily forsecuring the bit in place.

Another object is to provide a strong cutting bit which cannot be brokeneasily, and which will have a very effective cutting edge.

FIG. 1 is a side elevation of a representative form of chipper withparts broken away, and

FIG. 2 is a transverse section through the chipper taken on line 2-2 ofFIG. I.

FIG. 3 is a detail section on line 3-3 of FIG. 2.

FIG. 4 is a side elevation of the chipping drum on an enlarged scale.

FIG. 5 is a fragmentary enlarged radial section through a portion of thechipping drum showing a bit installation.

FIG. 6 is a section through such bit installation taken on line 66 ofFIG. 5.

FIG. 7 is a top perspective of the bit installation shown in FIG. 5.

FIG. 8 is an exploded top perspective of such bit in stallation.

FIG. 9 is a top perspective on a further enlarged scale of the bit shownin FIGS. 5 to 8, inclusive.

FIG. 10 is a plan of such bit, and

FIG. 11 is an end elevation of the cutting edge of such bit.

FIG. 12 is a longitudinal section through the bit taken on line l2l2 ofFIG. 11, and

FIG. 13 is a longitudinal section through the bit on line I3-l3 of FIG.11.

FIG. 14 is a fragmentary plan of a somewhat modified bit, and

FIG. 15 is an end elevation of the bit of FIG. 14.

FIG. 16 is a plan of a further modified form of bit,

FIG. 17 is a side elevation of such bit, and

FIG. 18 is an end elevation of the bit looking at the cutting edge end.

FIG. 19 is an inclined bottom view of the bit, viewing the cutting edgechamfers or bevel planes edgewise.

The present invention is concerned particularly with a cutting bit typeand with holders for cutting bits used in a chipper for cutting smalllog sections into chips. Such chipper includes a hollow body I in whicha chipping drum 2 is housed. Such drum is mounted for rotation on anaxle 3 carrying a pulley 4 which can be rotated by one or more belts 5,shown in FIGS. 1 and 2, driven by a motor 6. Small log sections, andparticularly those of short axial length such as the log wheel L shownin FIG. 2, can be delivered to the chipper by a supply conveyor 7.

The supply conveyor 7 will dump the log wheel L into the chippingchamber 8 in the upper portion of the hollow chipper body I in anattitude such that the axis of the log section extends generallyparallel to the axis of the chipping drum. The axial extent of the logsection is less than the corresponding width of the chipping chamber, asindicated in FIG. 1, in which the log section is shown in broken lines.Consequently, the periphery of the log round will engage the peripheryof the chipping drum. As shown in FIG. I, the axle 3 may be tilted toincline the axis of the drum 2 so that movement of the drum periphery incontact with the periphery of the log round will tend to urge the loground to move down to the broken line position shown in FIG. 1 in whichit is supported by the lower end wall of the chipping chamber, andconsequently cannot tip over.

The chip-cutting bits 9 are arranged in a spiral row around the chippingdrum 2, as shown best in FIGS, I and 4. Adjacent bits are arranged insufficiently overlapping relationship so that as the drum turns chipsare cut from the log round in successive layers. As shown in FIG. 4,each bit overlaps circumferentially the major portion of the width ofeach adjacent bit in an axial di rection.

As shown best in FIGS. 3, S and 6, the cutting bits 9' are received inapertures in the periphery of the drum 2, and the cutting ends of thebits project outward beyond the periphery of the drum and are spacedfrom the adjacent walls of the apertures to provide passages through thecircumferential drum wall for chips cut from a log section.Consequently, it is necessary to remove the chips from the interior ofthe drum. For this purpose chip-removing means are disposed within thedrum which in the chipper shown in FIGS. 1 and 2 is a chip-deflectorplate 10, shown best in FIG. 2 as being inclined axially of the chippingdrum for scooping the chips endwise out of the drum during its rotation.Such deflector plate is supported and positioned by struts l1 and 12secured to the chipper body.

As shown best in FIG. 2, the left wall of the chipping chamber 8 towardwhich the periphery of drum 2 turns is disposed in convergentrelationship to the adjacent portion of the drum periphery. Rotation ofthe upper portion of such drum toward such wall, in the directionindicated by the arrow, tends to move the log section in the directionof rotation of the drum periphery and to press the log section againstsuch wall. Continued rotation of the drum engaging one location of thelog sec tion will cut successive layers of such location into chips sothat such location of the log section will become concave complementalin curvature to the curvature of the chipping drum periphery. As morelayers are removed from the log section, such section will move fartherinto the angle between the converging chipping chamber wall and thechipping drum periphery. If the log section initially is round, iteventually will assume a crescent shape in cross section, as shown inbroken lines in FIG. 2.

Because of the direction of rotation of the chipping drum and the effectof such direction of rotation on the movement of the log section, anychips and debris which do not pass through the apertures in the drumperiphery will tend to accumulate in the angle between the convergingchipping chamber wall and the drum periphery. If excessive materialcollects in such angle,

it can be removed through an opening closed by an access door 13pivotally mounted on the hollow body by a pivot I4 to swing open fromthe solid-line closed position shown in FIG. 2. Such clean-out door canbe held in closed position by securing the lug or tongue [5 carried byits swinging edge to the adjacent wall of the body I by a bolt 16. Suchbolt can be removed and the lug or tongu'e pulled outward to swing thedoor open.

During operation of the chipper the edge 17 of a plate secured to thebody 1 adjacent to the clean-out door 13 serves as an anvil. The anviledge 17 is preferably in the form of fingers, as shown in FIG. 3,between which are notches 18 that will enable small pieces of debris andsmall stones to escape from the space between the converging chippingchamber wall and the drum periphery.

The spiral path around the drum 2 in which the bits 9' are mounted isdelineated by a spiral groove 19 in the drum wall and opening into theinterior of the drum, as shown best in FIGS. 3 and 5. The apertures 20in the wall of the drum in which the bits are mounted are located in thebottom of this groove. The bits 9' re ceived in these apertures are benttransversely of circumferential lines of the drum periphery and aredisposed at an angle to the drum periphery so that the cutting ends ofthe bits project outward beyond the drum wall as shown best in FIG. 5.

The pair of bit-holding blocks between which each bit is clamped fitsinto an aperture 20 in the drum periphery. The bit-clamping blocks shownin FIGS. 5, 6 and 7 include the inner block which is anchored in theinner portion of a drum aperture 20 by welding 31. Such block has anoutwardly inclined end portion, as shown in FIG. 5, which iscomplemental to the hollow inner side of the bit 9'. The slope of thebearing surface 32' provides shoulders 34' at the root ends of suchfaces against which the inner end of the bit 9' can abut to prevent suchbit from being driven inward by engagement of its cutting edges with alog being chipped.

The cooperating outer block 35 is also received in the aperture 20 inregistration with the inner block. The inner block 30 has a lug 36 overwhich the recess 37 in one end of the outer block 35 can fit. The opposite end of the outer block has a curved face 38' complemental to theinner block face 32. The outer block 35 can be held in clampingrelationship to the inner block 30 by a bolt 40 extending through anaperture 41 in the outer block and screwed into a tapped aperture 42 inthe inner block. The aperture 41 is counterbored to provide a shoulderagainst which the head of the bolt 40 can bear to press the loose block35 toward the fixed block 30.

As shown best in FIG. 5, the height of lug 36 is greater than the depthof the recess 37, so that the outer surface of the lug will engage thecorresponding surface of the recess when the mating surfaces of the twoblocks are spaced apart to provide a recess for reception of the bit 9between them. The lug 36 and recess 37 are proportioned to serve as afulcrum at one side of bolt 40 for providing clearance between the rootportions of the surfaces between which the bit is engaged at theopposite side of the bolt 40, so that as the bolt is tightened the tipsof the blocks 30 and 35 will clamp the opposite sides of the bitadjacent to its cutting edges, as shown best in FIG. 5.

The type of bit shown in FIGS. 5, 6 and 7 has a plate body 21'substantially smoothly curved between opposite edges. The body is ofsubstantially uniform thickness over at least most of its area. Such bitis substantially cylindrically curved transversely of a circumferentialline of the chipping drum. and the curvature of the bit shown in FIGS. 5to 13, inclusive, and in FIGS. 16 to 19, inclusive, is of the circulararcuate type. Its cutting end, extending between its opposite edges, isengrailed. being shown in FIGS. 7 to II, inclusive, as having a centralchamfer or flat bevel 42 and side chamfers or fiat bevels 43 meeting ininclined ridges 44. As shown in FIGS. 7 to 13, inclusive. the resultingcutting edges are concave and meet in cusps formed at the ends of theinclined ridges 44. The ends of the cut ting edges formed by the sidechamfers or bevels 43 constitute points 45. The cusps and end points ofthe engrailed cutting edge effect an initial penetration of the woodfollowed by a slicing action of the concave cutting edges which producesa very smooth cutting action rather than a chopping action.

For holding such a curved bit 9 between the clamping blocks 30 and 35the inner block 30 convex surface 32' substantially complemental to theconcave surface 38' of the outer block 35 formed so that the clampingeffect on the curved bit 9 will occur principally at a location adjacentto the cutting end of the bit as shown in FIG. 5, and also principallyon the central portion of the bit rather than on the bit edge portions,as shown in FIG. 6, to avoid application of pressure to the bit whichmight tend to break it.

The end ofa new bit can abut the shoulders 34' at the root of the convexbit-engaging surface 32 of block 30. As the bit is shortened bysharpening its cutting edge, it is desirable to compensate for suchshortening by building onto the inner end of the bit. For this purposethe inner end of the bit may have notches 46 in it as shown in FIGS. 9and 10, in which a babbitt lug 47 can be cast to abut the shoulders 34'of the block 30 to deter inward slippage of the bit.

While the curved cutter bit can be of circular arcuate cross section,the bit curvature may be modified, such as shown in FIGS. 14 and 15, sothat the curvature of the side portions of the bit body is somewhatsharper than the central portions. Such sharper curvature can beeffected by making the bit cross section of compound curvature, or ofelliptical, parabolic, or hyperbolic arcuate curvature. In the case ofan elliptical curvature the central plane of the bit body wouldsubstantially coincide with the minor diametral plane of the ellipticalare. All such curvatures are intended to be embraced within thedesignation of a substantially cylindrically curved bit, the definitionof a cylindrically curved surface being one traced by a straight linemoving parallel to a fixed straight line and intersecting a fixed curve.It is preferred that the curvature of the bit be such that its crosssection is symmetrical about a central longitudinal plane of the bit.

In the bit of FIGS. 14 and 15 the cutting end again is engrailed, beingformed by a central flat bevel 42' meeting side flat bevels 43 in ridges44'. Again the resulting engrailed cutting edge includes central andside concave cutting edges meeting at cusps and having end points 45'.The cutting action of the engrailed cutting edge of the bit shown inFIGS. 14 and 15 is similar to that of the bit shown in FIGS. 9 to 13,inclusive, but the chip cut will be of slightly different shape.

In both the bits of FIGS. 9 to 13 and of FIGS. 14 and 15 it is preferredthat the cusps and end points of the cutting edges be disposed in aplane substantially perpendicular to the body of the bit, andconsequently substantially perpendicular to the fixed straight line andto the generating straight lines which generate the opposite concave andconvex faces of the curved bit body. In some instances it may, however,be preferable for the ends of the two side cutting edge sectionsadjacent to the edges of the curved plate body, respectively, to bedisplaced lengthwise of the body back from the ends of the centralcutting edge section. Such a bit is shown in FIGS. 16 to 19, inclusive.

The bit shown in FIGS. 16 to 19, inclusive, has a curved plate body 21"which is shown as being of cylindrically curved shape. The cutting endof such body has a central chamfer or flat bevel 42" and side chamfersor flat bevels 43" meeting in inclined ridges 44". The resulting cuttingedges are concave as in the previous bits and meet in cusps at the endsof the inclined ridges 44". The outer ends of the side cutting edgesform points 45".

The distance between the cutting edge cusps 44, 44' or 44" determinesthe length of the chip cut. Such distance may be from three-quarters ofan inch to one and one-quarter inches, for example. The greater thedistance between the cusps, the longer will be the chip cut.

I claim:

1. A bit for mounting in an aperture of a rotary chipping drumcomprising an arcuate plate body approximately 90 in extent, ofsubstantially uniform thickness over at least most of its area, havingsubstantially parallel opposite edges, being substantially smoothlycurved throughout its width between said opposite edges and having acutting edge extending transversely of said opposite body edges andbetween said opposite body edges, said cutting edge having two bevelsmeeting in a ridge and forming adjoining concave cutting edges meetingin a cusp, and said plate body being discontinuous between said oppositeedges opposite said cutting edge, enabling chips cut by said cuttingedge to pass directly radially of said arcuate plate body through theaperture in the chipping drum.

2. The bit defined in claim 1, in which each bevel is flat.

3. The bit defined in claim 1, in which the cutting edge of the bitplate body has three sections including a central section and two sidesections, each of said sections having a bevel, the bevels of said sidesections meeting the bevel of said central section in a ridge, each ofsaid bevels defining a concave cutting edge section, and each of saidside cutting edge sections meeting said central cutting edge section ina cusp.

4. The bit defined in claim 3, the ends of the side cutting edgesections and the cusps at the junctions of the two side cutting edgesections with the central cutting edge section being substantially in aplane perpendicular to the parallel opposite edges of the curved platebody.

5. The bit defined in claim 3, the ends of the two side cutting edgesections adjacent to the parallel opposite edges of the curved platebody, respectively, being displaced lengthwise of the parallel oppositeedges of the body back from the cusps at the junctions of the two sidecutting edge sections with the central cutting edge section.

6. The bit defined in claim 1, in which the cross section of the bitplate body is a compound curve.

7. The bit defined in claim 6, in which the opposite edge portions ofthe bit plate body are curved more sharply than the central portion ofthe bit plate body.

8. The bit defined in claim 1, in which the bit plate body is anelliptical are.

9. The bit defined in claim 8, in which the central plane of the bitplate body substantially coincides with the minor diametral plane of theelliptical arc.

10. In a peripheral chipper including a rotary chipping drum havingapertures therein arranged around its periphery, a plurality of bits,and means for mounting the bits in such respective apertures of the drumwith their ends leading in the direction the bits are moved by rotationof the chipping drum forming cutting edge portions projecting beyond thedrum periphery, the improvement comprising each bit being an arcuateplate body approximately in extent, curved relative to a straight lineextending transversely of the direction of bit movement, ofsubstantially uniform thickness over at least most of its area, havingsubstantially parallel opposite edges, being substantially smoothlycurved throughout its width between said opposite edges and having acutting edge extending transversely of said opposite body edges andbetween said opposite body edges, said cutting edge having two bevelsmeeting in a ridge and forming adjoining concave cutting edges meetingin a cusp, and said plate body being discontinuous between said oppositeedges opposite said cutting edge, enabling chips cut by said cuttingedge to pass directly radially of said arcuate plate body through theaperture in the chipping drum.

11. In the chipper defined in claim 10, the cross section of a bit beinga plate having a compound curve.

12. In the chipper defined in claim 11, the opposite edge portions ofthe bit plate being curved more sharply than the central portion of thebit plate.

13. in the chipper defined in claim 10, the bit being a plate curved inan elliptical arc.

14. In the chipper defined in claim 13, the central plane of the bitplate substantially coinciding with the minor diametral plane of theelliptical arc,

W195? UNITED STATES PATENT OFFICE 5 CERTIFICATE OF CORRECTION Patent No.3 892 Z65 Dated July L 1975 Inventor) Stanley Donald Vanek It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Title page, Section 63, line 2, change "1973" to ].971-;

Section 57, line 6, change "edges" to -eclge--.

Signed and Sealed this sixth D y of January 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner nj'laremsand Trademarks

1. A bit for mounting in an aperture of a rotary chipping drumcomprising an arcuate plate body approximately 90* in extent, ofsubstantially uniform thickness over at least most of its area, havingsubstantially parallel opposite edges, being substantially smoothlycurved throughout its width between said opposite edges and having acutting edge extending transversely of said opposite body edges andbetween said opposite body edges, said cutting edge having two bevelsmeeting in a ridge and forming adjoining concave cutting edges meetingin a cusp, and said plate body being discontinuous between said oppositeedges opposite said cutting edge, enabling chips cut by said cuttingedge to pass directly radially of said arcuate plate body through theaperture in the chipping drum.
 2. The bit defined in claim 1, in whicheach bevel is flat.
 3. The bit defined in claim 1, in which the cuttingedge of the bit plate body has three sections including a centralsection and two side sections, each of said sections having a bevel, thebevels of said side sections meeting the bevel of said central sectionin a ridge, each of said bevels defining a concave cutting edge section,and each of said side cutting edge sections meeting said central cuttingedge section in a cusp.
 4. The bit defined in claim 3, the ends of theside cutting edge sections and the cusps at the junctions of the twoside cutting edge sections with the central cutting edge section beingsubstantially in a plane perpendicular to the parallel opposite edges ofthe curved plate body.
 5. The bit defined in claim 3, the ends of thetwo side cutting edge sections adjacent to the parallel opposite edgesof the curved plate body, respectively, being displaced lengthwise ofthe parallel opposite edges of the body back from the cusps at thejunctions of the two side cutting edge sections with the central cuttingedge section.
 6. The bit defined in claim 1, in which the cross sectionof the bit plate body is a compound curve.
 7. The bit defined in claim6, in which the opposite edge portions of the bit plate body are curvedmore sharply than the central portion of the bit plate body.
 8. The bitdefined in claim 1, in which the bit plate body is an elliptical arc. 9.The bit defined in claim 8, in which the central plane of the bit platebody substantially coincides with the minor diametral plane of theelliptical arc.
 10. In a peripheral chipper including a rotary chippingdrum having apertures therein arranged around its periphery, a pluralityof bits, and means for mounting the bits in such respective apertures ofthe drum with their ends leading in the direction the bits are moved byrotation of the chipping drum forming cutting edge portions projectingbeyond the drum periphery, the improvement comprising each bit being anarcuate plate body approximately 90* in extent, curved relative to astraight line extending transversely of the direction of bit movement,of substantially uniform thickness over at least most of its area,having substantially parallel opposite edges, being substantiallysmoothly curved throughout its width between said opposite edges andhaving a cutting edge extending transversely of said opposite body edgesand between said opposite body edges, said cutting edge having twobevels meeting in a ridge and forming adjoining concave cutting edgesmeeting in a cusp, and said plate body being discontinuous between saidopposite edges opposite said cutting edge, enabling chips cut by saidcutting edge to pass directly radially of said arcuate plate bodythrough the aperture in the chipping drum.
 11. In the chipper defined inclaim 10, the cross section of a bit being a plate having a compoundcurve.
 12. In the chipper defined in claim 11, the opposite edgeportions of the bit plate being curved more sharply than the centralportion of the bit plate.
 13. In the chipper defined in claim 10, thebit being a plate curved in an elliptical arc.
 14. In the chipperdefined in claim 13, the central plane of the bit plate substantiallycoinciding with the minor diametral plane of the elliptical arc.